Vitamin D and the fortification of milk

1941 saw the exposure of solar exposure and cancer risk.  Later studies found associations with low vitamin D levels associated with type 1 diabetes mellitus, autoimmune issues such as inflammatory bowel disease, MS and animal studies supported low vitamin D causing increased inflammation and cancer.

Adequate levels of 25 hydroxyvitamin d (OHD25) is considered a level of about 50nmol/L at the end of winter and 10-20nmol/L higher at the end of summer. The institute of medicine vs the endocrine society state the guidelines inappropriately conclude the benefits of vitamin d are at 75nmol/L 25OHD and above. Mistakenly concluding all persons with serum 25OHDlevels below 50nmol/L are deficient.

UK DoH recommends a plasma concentration of 25nmol/L

In 2016 public health england published a report advising that 10 micrograms are advised daily to support bones, teeth and muscle. This advice was published in line with recommendations from SACN to suggest this safe level for everyone over 4 years old. SACN did not take into account the vitamin D from sun exposure as the synthesis of the vitamin through the skin is complex. PHE advises that throughout the months from March until October the majority of the public gain enough vitamin D through sunlight and a balanced diet.  During the winter, dietary sources are relied on.  IT is difficult for people to meet the 10 microgram recommendation. Fortification of foods will assist with those who are less likely to get out in sunlight and those who do not consume enough naturally through diet.

Deficiency  - corresponds with blood levels with clinical evidence of bone disease such as rickets or osteomalacia. Once levels are below 20-25nmol/L a very high risk is present.
Insufficiency is a biochemical term. No clinical evidence of disease is present. PTH levels may be elevated in the blood.
Some studies do not differentiate yet the differentiation will really determine a change of numbers reported on the studies.

A large number of studies exist to show low 25OHD is associated with increased risk of cardiovascular disease, hypertension, type 2 diabetes mellitus, cancer, autoimmune disease and increased mortality.

Is vitamin D simply a good marker for health? Were the randomised control trials started early enough? Were these studies including looking at calcium?

Vitamin D toxicity is rare but potentially serious.
HypervitaminosisD is not caused by diet or sum exposure but rather intake of a supplement at levels of 60,000 IU a day for several months.  As the body regulates the vitamin D produced from sun absorption really very well, fortification may be an excellent answer to gain better status levels from the diet.  Fortified foods do not contain major amounts of vitamin D and are regulated closely.
Toxicity from vitamin D has a main consequence of hypercalcemia in the blood. Symptoms noted are nausea, increased urination and weakness.  Possible progression pathways are into bone pain, kidney problems and the formation of calcium stones. Treatment includes stopping vitamin D intake and restricting calcium in the diet.

Naturally occurring vitamin D can be found in fatty fish and fish liver oils.  A plant source of vitamin d is mushrooms although this is vitamin d2 yet animal products contain vitamin d3.

The largest source of dietary vitamin d is fortified foods.  Namely milk, orange juice and cereals.
Vitamin D is essential to bone metabolism and calcium absorption.
Vitamin D deficiency is common among older adults as they have impaired ability to synthesise vitamin d from the sun